Closure device

ABSTRACT

An improved closure apparatus for use with injection molding devices and the like in which a rigid brace pivoted into operative position between a force producing source and a reciprocating working member has a grooved sliding guide portion in which a slide ring is movable. The slide ring is pivotally connected to a piston rod actuable by a stationary hydraulic cylinder. The rigid brace is pivoted through an angle of 90* and means are provided for automatically controlling the actuation of the force producing source in dependency on the position of the rigid brace. The closure device is readily usable with a variety of mold heights.

United States Patent [191 F lorjancic [451 Sept. 25, 1973 CLOSURE DEVICE[22] Filed: Mar. 11, 1971 [21] Appl. No.: 123,151

[30] Foreign Application Priority Data Mar. 25, 1970 Austria A2793/70[52] US. Cl 92/129, 91/189, 92/61 [51] Int. Cl Fl6j 1/10 [58] Field ofSearch 92/62, 129, 140,

92/61; 100/270, 271; 18/30 A, 30 B, 30 C, 30 D, 30 E, 30 F, 30 M, 30 LV,3O LT; 91/189 [56] References Cited v UNITED STATES PATENTS 3,137,2126/1964 Rose 91/189 3,345,691 10/1967 Aoki 18/30 LV 3,423,502 1/1969Stimpson..... 18/30 LV 3,597,798 8/1971 McDonald... 18/30 LV 3,327,3536/1967 Eggenberger 18/30 LA CONTROL U/V/ T 3,165,796 1/1965 McDonald18/30 LM FOREIGN PATENTS OR APPLICATIONS 108,468 7/1967 Denmark 18/30 LV1,529,898 5/1969 Germany 18/30 LM Primary Examinerlrwin C. CohenAttorney-Bryan, Parmelee, Johnson & Bollinger [57] ABSTRACT An improvedclosure apparatus for use with injection molding devices and the like inwhich a rigid brace pivoted into operative position between a forceproducing source and a reciprocating working member has a groovedsliding guide portion in which a slide ring is movable. The slide ringis pivotally connected to a piston rod actuable by a stationaryhydraulic cylinder. The rigid brace is pivoted through an angle of 90and means are provided for automatically controlling the actuation ofthe force producing source in dependency on the position of the rigidbrace. The closure device is readily usable with a variety of moldheights.

3 Claims, 2 Drawing Figures PATENTED SEP25 I973 CONTROL UNI T CLOSUREDEVICE BACKGROUND OF THE INVENTION This invention relates to anapparatus for reciprocating a working member to a working position forhigh pressure close working as particularly applied to an injectionplastic molding apparatus.

In my copending application Ser. No. 43.706 entitled CLOSURE APPARATUSand filed June 5. I970 now U.S. Pat. No. 3,691,913, I disclosed aworking member which is mounted for reciprocating movement relative to aforce producing source in an injection molding machine. In thatinvention a rigid brace is pivoted into operative position between theforce producing source and the working member when the latter hasreached a working region by means of a piston operatively seated in acylinder, the cylinder being pivotally connected at a fixed fulcrum. Thespeed of the pivoting movement could thus be controlled.

SUMMARY OF THE INVENTION In an apparatus for reciprocating a workingmember to a working position for high pressure working in accordancewith the invention, a rigid brace is pivoted over an extended anglebetween generally transversely disposed positions. The working member ismounted for reciprocation along a line of advancement between a forceproducing source and a working region to perform high pressure work suchas the closing of an injection mold. The rigid brace is mounted to pivotto a first position which is parallel with the line of advancement to asecond pivoted position which is generally transverse to the line ofadvancement. With the rigid brace in the first pivot position, the forceproducing source and the working member are operatively coupled to oneanother through the rigid brace. In the second pivot position of therigid brace the working member is retracted from the working region nearthe force producing source with the pivoted rigid brace therebetween toform a compact apparatus for reciprocating the working member.

In a closure apparatus utilizing a rigid brace with limited pivotalangular movement such as described in a specific embodiment in theabove-identified copending application, the rigid brace is pivoted intooperating position by means of a rod pivotally connected to the brace atone end and to a piston within a cylinder at the other end. The cylinderis pivotally mounted at a fixed fulcrum on the machine frame. Anadvantage of the improved closure apparatus in accordance with thisinvention resides in that the cylinder need not pivot and may be fixedlymounted.

An advantage of a closure apparatus in accordance with this invention isthe reduction of the number of articulated joints and moving parts, aswell as a short construction length of machine and a more efficienttransmission of the high pressures.

An object of the invention, therefore, is the provision of a closureapparatus in which the rigid brace consists partially of a groovedsliding guide portion in which a slide ring or roller is movable. Apiston rod is pivotally connected to the slide ring at one end and to apiston situated in a hydraulic cylinder at its other end. the hydrauliccylinder is stationary and fixably mounted.

As a result of fixably mounting the hydraulic cylinder the hydraulicfluid feed lines need not be flexible but can be constructed from rigidstrong materials therefore reducing damage thereto. Moreover, thehydraulic cylinder may be placed in closer proximity to the forceproducing source and does not occupy any space in the region adjacentthe working member in the working region or path. The latter featuresmake the inspection and replacement of the cylinder possible with aminimum of inconvenience.

A further object of the invention is the provision of a means whichpermits automatic control of the actuation of the force producing meansas a function of the rigid brace position. Moreover, the speed of thepivoting rigid brace is controllable.

Another object of the invention is the provision of a hydraulic closuredevice for injection molding machines in which a closure plate can bemoved from an open position against an immovable clamping plate into aclosed position by a hydraulic feed cylinder of relatively low power andhigh speed, the closure plate having a rod shaped rigid brace mountedfor pivot movement in a vertical plane. The rigid brace pivots betweenthe closing plate and a high pressure piston and is permitted to turnthrough an angle of at least so that it may extend either parallel to orradially from the axis of the machine.

An additional advantage of the invention is that the rigid brace andcylinder may be used with injection molding machines of different sizesand heights since the only adjustment to be made is in the stroke of thepiston of the hydraulic cylinder.

A further advantage is the improved ejection of the molded articleswhich may be permitted to drop down freely without interference from therigid brace or hydraulic cylinder.

It is, therefore, an object of the invention to provide an improvedclosure apparatus for injection molding device and the like.

DESCRIPTION OF THE DRAWING Other advantages and objects of the inventionmay be understood in the following description of embodiments of theinvention schematically illustrated in their intermediate positionbetween open and closed positions in the accompanying drawing in which:

FIG. 1 illustrates an embodiment of the closure apparatus in which therigid brace is linear, showing also, in labeled representation, theembodiment utilizing a control unit; and

FIG. 2 illustrates an embodiment of the closure apparatus in which therigid brace is curved.

DETAILED DESCRIPTION OF THE EMBODIMENTS Referring to FIG. 1 there isshown a working member in the form of a closure plate 11 for aninjection mold (not shown). Closing and opening motions of the closureplate 11 are hydraulically controlled by piston rods located incylinders, which are fast acting but of relatively low force. The piston5 is operatively located in a high pressure cylinder head 4 and iscapable of producing a high pressure force. The just describedcomponents are more specifically shown and discussed in one of theirintended environments, an injection plastic molding machine, in mycopending application referred to above.

A rigid brace denoted generally at 17 is pivotally connected to theclosure plate 11 by means of a fulcrum pin 18 passing through a pillowblock 19 which is fixed to the closure plate 1 l. The central portion ofthe rigid brace 17 consists of a sliding guide 44 having a groove ortrack within which moves the slide ring or roller 45. The slide ring 45is pivotally attached to the end of the piston rod 33 of a piston 35which is operatively seated in a cylinder 34 of a hydraulic unit 30. Thecylinder 34 is fixed in a stationary manner to the injection moldingmachine frame and receives its operating fluid via feed pipes (notshown) in the conventional manner.

The position of the components schematically corresponds to that shortlybefore the end of a closing movement. The closure plate 11 has beenmoved to the right by piston and cylinder means (not shown) and thepiston 35 is acted upon from below causing the rod 33 to lift the rigidbrace 17 through action of the guide 44 sliding on ring 45. The rigidbrace 17 is lifted until it opposes the extension 6 of the high pressurepiston with its free end. Piston 5 is then actuated by pressure fluidand transmits great force through the rigid brace 17 to the closureplate 11 to strongly press the latter to the right against a rigid halfof an injection mold (not shown). Upon completion of a desiredoperation, such as an injection molding step, the piston 5 is releasedby action of pressure fluid upon it from the right and the piston 35 ismoved downward by means of fluid pressure acting upon its top surface.The components are then again in the position illustrated.

In further operation the closure plate 11 is moved to the left by aconventional return piston (not shown) causing the rigid brace 17 toswing downward while the sliding guide 44 slides over the non-movingslide ring 45. In the completely opened position of the closure plate 11and the mold the rigid brace 17 assumes a substantially verticalposition, extending radially from the axis of the machine. Thus, it isseen that the rigid brace is permitted to pivot through an angle ofapproximately 90.

The construction and operation described requires that the rigid brace17 and the hydraulic unit be positioned laterally displaced from oneanother. Thus, the hydraulic unit 30 can be located outside of themachine axis a special advantage in machines with extremely high closingforces. Additionally, two laterally positioned rigid braces or abifurcated rigid brace can be provided.

Another embodiment according to the invention utilizes a locking deviceto maintain the closure plate in the extreme closed position thuslocking the mold. Referring to the drawing there is shown an arm 36connected to the piston 35. A switch 40 diagramatically shown as a pairof contacts 46 controls release of the pressure fluid feed from thepump, represented by labeled representation, to the piston 5 for itsmovement by means of conventional control unit, as represented by thelegend. Switch 40 is opened or closed depending upon the position of arm36, the movement of which is controlled by the piston 35. When thepiston is in a uppermost position and rigid brace 17 extends betweenclosure plate 11 and the extension 6, the contacts will touch oneanother thus closing switch 40. If there is an obstacle between thehalves of the mold interfering with its closing, the relatively lowpower of the hydraulic unit 30 is insufficient to press the rigid braceentirely upward to a position parallel to the machine axis and thereforethe contacts 46 cannot be closed. Since switch is not closed thepressure fluid is not introduced behind piston 5 to actuate it thereforepreventing damage to the halves of the mold, as for example caused byextrusion of material through a slit between mold halves.

The switch 40 also controls the pressure oil feed for the return of thepiston 5. The rigid brace 17 is kept in its upright position due to thefriction between its free end and the extension 6 of the piston 5 whenpiston 5 is acting upon it. The power of hydraulic unit 30 isinsufficient to overcome this frictional force; however, as soon as thepivoting rigid brace 17 becomes free as the piston 5 moves to the leftthe piston 35 of hydraulic unit 30 moves downward causing arm 36 to movedownward and open switch 40 thus interrupting the oil feed to the righthand side of the piston 5 which then ceases motion A distinct advantageof the invention, therefore, as compared to the conventional moldclosing devices which are attached to the closure plates themselves isthat the present improved closure device may be changed over to a moldof a different height without need of adjustment. The same switch 40automatically causes the fluid requirement for the pressure piston 5 tobe a minimum and the time of the opening to be as short as possible.

Many different embodiments are possible within the framework of theinvention. In particular, as shown in FIG. 2 having like numbersrepresenting like elements of FIG. 1, the sliding path of the guide 44of the rigid brace 17 need not be straight but may be shaped in a curveso as to influence the swinging or pivotal speed of the rigid plate independency upon the displacement of the closure plate 11. For example,the distance and space required for the swing can be reduced by shapingthe sliding path in the vicinity of the closure plate concave anddownwards. As a maximum, this part of the sliding path could runhorizontal in the open position.

As an additional variant, the piston 35 of the hydraulic unit 30 couldbe rendered immovable while the cylinder 34 would carry a rod 33 and thesliding ring 45 and move about the piston 35. In this instance, aflexible pressure oil feed lines would be required or alternatively thepressure oil supply could be sent through hollow piston rod. Also, amechanical force transmitting means could be substituted for thehydraulic unit 30.

What has been provided, therefore, is an improved rigid brace which maybe pivoted through an angle of 90 rapidly and controllably into positionbetween a working member and a high pressure applying means. Inaddition, the hydraulic fluid feed to the high pressure piston is madeautomatically controllable by the position of the rigid brace.

What is claimed is:

1. In an apparatus for moving a closure member along a line ofadvancement, the improvement comprising a rigid brace having a free endand a pivoted end, means pivotally connecting said pivoted end to saidclosure member for pivoting said brace from a first position in parallelalignment with the line of advancement to a second position generallytransverse thereto, a force producing means arranged to abut said freeend I of the rigid brace and exert a force along the line of advancementwhen in the first position, the rigid brace being provided in itscentral longitudinal portion with a sliding guide having a groovetherein, a slide ring positioned in the groove so as to slide therein, acylinder with a piston therein, a movable rod attached to said piston,means coupling the slide ring to said movable rigid brace extends whenin the second position whereby the pivotal speed of the rigid brace isdependentin part on the displacement of the closure member and the spacerequired for the positioning is significantly reduced.

3. An apparatus as claimed in claim 1, wherein said force producingmeans comprises a switch-controlled hydraulically operatedcylinder-piston assembly.

1. In an apparatus for moving a closure member along a line ofadvancement, the improvement comprising a rigid brace having a free endand a pivoted end, means pivotally connecting said pivoted end to saidclosure member for pivoting said brace from a first position in parallelalignment with the line of advancement to a second position generallytransverse thereto, a force producing means arranged to abut said freeend of the rigid brace and exert a force along the line of advancementwhen in the first position, the rigid brace being provided in itscentral longitudinal portion with a sliding guide having a groovetherein, a slide ring positioned in the groove so as to slide therein, acylinder with a piston therein, a movable rod attached to said piston,means coupling the slide ring to said movable rod, means stationarilymounting said cylinder relative to the other components and having anaxis running substantially normal to the axis of the line of advancementof the closure member, to move the rigid brace to and from its positionof alignment between the closure member and the force producing means.2. An apparatus as claimed in claim 1 wherein the groove in the slidingguide of said rigid brace is curved near its pivoted end towards thedirection in which the rigid brace extends when in the second positionwhereby the pivotal speed of the rigid brace is dependent in part on thedisplacement of the closure member and the space required for thepositioning is significantly reduced.
 3. An apparatus as claimed inclaim 1, wherein said force producing means comprises aswitch-controlled hydraulically operated cylinder-piston assembly.